Many modules for coupling a laser diode or a photodetector to a wave guide, for example, are known, either in the form of conventional type optical fiber or in the form of integrated wave guides. In general, the coupling of optical components is a critical aspect in the design of optical apparatus because, in numerous applications, there is a requirement to ensure a high efficiency of coupling to allow optimum transfer of the radiation between the components themselves.
To obtain a high efficiency, due to the typical dimensions in question (on the order of a tenth of a micron), considerable accuracy is required in the mutual alignment and positioning between the devices to be coupled. This accuracy significantly affects the cost of production of an optical apparatus.
On this subject, U.S. Pat. No. 6,053,641 describes a module comprising a laser diode arranged on a support base, and a spherical lens held in position by a cap that rests on the support base itself. The lens is optically coupled to an optical fiber housed in a respective ferrule supported by a structure composed of two cylindrical elements welded together and globally resting on the support base.
U.S. Pat. No. 5,537,503 describes a semiconductor optical module including a light emission device, a lens that makes the light emitted by the device convergent and a glass fiber inserted into a ferrule. The module described in this patent also comprises a complex structure formed by a number of mechanical connection and support elements that hold in position the optical components to be coupled.
Conventional optical modules have the drawback of being relatively expensive and offering poor coupling efficiency unless complex techniques of alignment of the optical components are used.